I want to know what is wrong in the following sentence:

Question

After six months on the job, he faced problems in his first recruitment effort; however, if he solves these problems, the new hires should be able to start working by July.

Answer 1

You have switched verb tenses.

Answer 2

http://grammar.ccc.commnet.edu/grammar/consistency.htm

Answer 3

hires sounds a little awkward. i think hirees should be placed in there instead of hires